1. Field of the Invention
The present invention generally relates to adaptive optics. Specifically, the invention is a device wherein the shape of an optical element is altered via an array of actuators controlled by a power distribution network. The power distribution network includes a matrix architecture having a high-speed microcontroller, digital signal processor, or field programmable gate array therein.
2. Description of the Related Art
Active and adaptive optics refer to optical systems that dynamically modulate the shape of a mirror in real time to compensate for atmospheric conditions and/or variations along or within an optical material. For example, adaptive optics may compensate for atmospheric turbulence so that very faint objects may be imaged in long exposures. In another example, adaptive optics may compensate for variations along or within an optical material related to defects or changes resulting from motion, gravity and temperature. Adaptive optics offer image quality approaching the theoretical diffraction limit. One advantage of adaptive optics is that fainter objects can be detected and studied when light levels are very low.
An adaptive optics system includes an element, usually a deformable mirror, to restore a wavefront by applying a canceling distortion based upon the shape of the distorted wavefront. Exemplary adaptive optics systems use a point source of light, one example being a star, as a reference to probe the shape of a wavefront. Light from the reference source is analyzed by a sensor and commands are communicated to a mechanical device which alters the surface of a deformable mirror to provide the necessary compensations. An adaptive optics system must adjust the shape of an optical element at least several hundred times per second to effectively remove atmospheric distortions and/or variations along an optical surface so as to achieve the best possible image quality.
The application of active material actuators, including PMN and PZT elements, requires precise control of multiple actuators within an array. Precise control is directly related to the power delivery method.
Power control approaches are known within the art whereby small charge packets are used to control actuators. This approach offers both efficient power-to-mechanical-force conversion and very high resolution or accuracy. However, devices employing this approach are inherently gain-bandwidth product limited due to the reliance on small charge packets. As such, this approach does not adequately correct distortions and variations encountered by many optical systems.
Power control approaches are also known within the art whereby each actuator is assigned a power amplifier so as to allow for the separate control of all actuators within an array. However, several deficiencies prohibit practical implementations of this approach. First, the complexity and size of conventional wiring buss designs increase with actuator density, thereby causing electromagnetic interference, radio frequency interference, and capacitive loss problems. Second, the size and complexity of the power electronics prohibit actuator densities required to adequately control a contiguous optical element.
What is currently required is an adaptive optics system having a power distribution and control system that avoids the problems of the related arts while providing a compact, affordable and reliable solution.